It has been known that sports balls including athletic balls are manufactured by adhering cloth pieces to the surface of a hollow spherical rubber bladder inflated with air injected into it, to form a cloth reinforcement layer on the bladder, or by winding around the surface of such a rubber bladder a synthetic fiber yarn impregnated with latex adhesive solution, to form a yarn winding reinforcement layer on the bladder, and by adhering surface panels to the overall surface of the cloth or yarn winding reinforcement layer after vulcanizing and forming the rubber bladder with the reinforcement layer; or as disclosed in Patent Publication Sho58-29112 (Patent Document 1), by forming a hollow sphere from fragile material such as paraffin, forming a cloth bag from cloth pieces adhered doubly to the outer surface of the hollow sphere, taking the hollow sphere out of the cloth bag through an opening formed by cutting out a portion of the cloth bag, inserting a rubber bladder through the opening into the cloth bag, stacking a rubber sheet on overlapped end portions of the adjacent cloth pieces of the bag after the rubber bladder is inflated with air injected into it, forming the rubber sheets into ridge-like ribs by vulcanizing and forming them, and adhering surface panels to the surface of the cloth pieces on the bladder along the ridge-like ribs.
The former ball has the advantage of improved strength of the ball, due to the fact that the bladder is reinforced with the yarn windings or the cloth pieces, whereas the latter ball has the advantage of being capable of absorbing impact from the exterior due to separation of the outer surface of the bladder from the inner surface of the cloth bag in which the bladder is inserted.
However, the former ball has a hard feel and high impact force due to the triple layers of rubber bladder, yarn winding or cloth reinforcement layer, and the surface panels in a stacked and adhered state, whereas the latter ball has a soft feel due to separation of the bladder from the cloth bag as disclosed above, but the requirement of complicated steps for manufacture of the cloth bag results in low production efficiency.
It is disclosed in Utility Model Publication Sho36-31132 (Patent Document 2) that there is provided an athletic ball manufactured by winding, at random, a fabric tape around the outer surface of a spherical hollow rubber bladder inflated with air injected into it, sticking surface rubber on the wound fabric tape and vulcanizing and forming the whole. This ball has better production efficiency as compared with the ball with the yarn windings or the cloth, since the fabric tape is wound around and stuck on the outer surface of the rubber bladder, but the fabric tape wound around the rubber bladder at random and stuck on it, has the disadvantage of losing the function of absorbing impact force exerted on the ball, due to lost directional property of the cloth construction. In this prior art, heat vulcanization of the whole, including the surface rubber, further facilitates a hard feel.
Patent Document 1: Patent Publication Sho58-29112
Patent Document 2: Utility Model Publication Sho36-31132
An object of the present invention is to provide a sports ball capable of relieving the pain of the hands suffered from impact on the ball and having a soft feel and high flexibility.
This object of the invention can be achieved by providing a sports ball comprising a spherical hollow rubber bladder inflated with air injected into it, a fabric tape reinforcement layer formed by winding a narrow adhesive-impregnated fabric tape around a central spherical portion of the rubber bladder about each of three axes of the rubber bladder, with the exception of opposite spherical end portions of the rubber bladder, whereby the fabric tape reinforcement layer is formed as orthogonal lap windings of the fabric tape over substantially all of the spherical surface of the rubber bladder to provide a fabric tape wound ball core, and surface panels adhered with adhesive to the fabric tape reinforcement layer on the rubber bladder after vulcanization and forming of the fabric tape wound ball core.
According to the invention, the fabric tape is wound around the rubber bladder with the wound adjacent portions of the fabric tape overlapping each other by ½ of the width of the fabric tape, such that two layers are formed per each of the three axes of the rubber bladder. The fabric tape preferably is comprised of cotton, or polyester, or mixed fabric of cotton and polyester, or hemp, or mixed fabric of hemp and polyester. The fabric tape preferably has a width of about 10% of a diameter of the rubber bladder.
In a preferred embodiment of the invention, the surface panels each may comprise a urethane layer, backed by a foam sponge layer.